Many penguins live in environments that don't offer fresh water. Those who live in Antarctica, for example, have a choice of ice or saltwater. Saltwater is more convenient and easier to obtain, so that's where penguins tend to get their water. They have a special adaptation to help keep their bodies' salt levels balanced.
How They Drink
Penguins drink the same way most birds do: by swallowing water. Although that's nothing special, penguins often have little choice but to swallow saltwater. When they're swimming in the ocean, they use their strong beaks to catch fish and other prey. Opening their mouths while they're swimming at full speed means they're going to catch some water while snagging dinner. They often swallow prey whole, taking saltwater down with it.
Penguins are specially designed to process saltwater, even though their bodies don't need more salt than other animals. They have a supraorbital gland located near their eyes that filters salt out of their systems. Their blood travels through the gland, which traps the salt before it travels through their bodes.
When the supraorbital gland filters salt out of a penguin's blood, it must still get the excess salt out of the penguin's body. Salt in the gland mixes with a small amount of moisture inside the gland and travels down the nasal passages. These salt-laden drops drip out the penguin's nose. Penguins often shake their heads to release the drops and get salt off their beaks.
Penguins can drink saltwater, but they have no trouble drinking fresh water if it's available. Some even eat snow as a source of water. Penguins in zoos live in fresh water, and some species, such as rockhopper penguins, prefer to live around fresh water instead of saltwater. The supraorbital gland serves only one purpose -- to filter salt from the blood -- so it's not used when penguins drink only fresh water. There are no health problems associated with penguins taking a clear drink, hold the salt.
Tom Brakefield/Stockbyte/Getty Images